Study On Semi-active Control For Seismic Response Of Beam Bridges Based On Inverse Model Of MR Damper

Magnetorheological (MR) damper has simple configuration and good control effects. As one of the most promising semi-active control devices for the seismic response control in the civil engineering, MR damper has aroused the wide attention of scholars around the world. In the thesis the theoretical research and simulation analysis of MR damper for semi-active control based on the adaptive inverse model were systematically carried out. The main research work and results include the following aspects:1. According to the algorithm to adaptively identify the MR damper model parameter, the adaptive identification model was established in Matlab/Simulink platform based on the modified LuGre friction model. Through a large amount of simulations, the characteristic parameters of the model were analyzed, and the initial values of parameters and the steps were established. Based on the adaptive identification model, the parameters of the modified Bouc-Wen hysteretic model of MRF-04K damper was identified as an example. The results indicate that the hysteretic curve obtained by the modified LuGre friction model with online updated parameters has a high alignment with that obtained by modified Bouc-Wen model, and can precisely describe hysteresis characteristics of the MRF-04K damper.2. Combined the hysteresis model of MRF-04K damper with LQG active control algorithm, the thesis conducted some simulations for a three-layers frame structure under the excitation of three different seismic waves based on the adaptive inverse model algorithm and Clip-optimal control algorithm respectively. The results present that the semi-active control system based on the adaptive inverse model can effectively control the displacement and acceleration responses of the controlled structure. Comparision and analysis of the implementation mechanisms of two semi-active control strategies indicate that the adaptive inverse model algorithm can track the active control force calculated by LQG algorithm better by continuously adjusting the input voltage, which is the nearer to the active control effect.3. Compared with Clip-optimal control algorithm, this thesis applied the adaptive inverse model semi-active control system in Highway Bridge Benchmark model to conduct seismic response reduction simulation analysis under the excitation of six different seismic waves. The results indicate that the adaptive inverse model algorithm can effectively achieve the seismic response reduction of beam bridge. Meanwhile, the seismic response reduction, especially structural response peak reduction, is superior to that of the Clip-optimal control algorithm and nearer to the results of the LGQ active control. These results provide reliable theory basis for experimental study on seismic response reduction of beam bridge and engineering application using the semi-active control system of MR damper based on the adaptive inverse model.